All of them have little command line programs. You have to run specific commands, in a specific order. Each one does... things. Many things, grabbing stuff from all over the Internet. You have no idea what any of these other things are, but there sure are a lot of them. Do you need them? Dunno, guess so, but where do they come from? Your directory tree starts growing many leaves and branches. But wait, you made a small change, you have to run something else to make it pick up the change and re-something the whozit or your application throws inscrutable errors. You start to despair, so you begin reading documentation. All of the documentation is cheery and bright, telling you how wonderful this or that package or tool is, so now you feel like a moron because you simply don't understand what's happening.
You give up and become a pea farmer.